2012淘金英语专业四级听写 上海外国语大学 请从正文部分开始听写
A rainbow is a circle of colors that appears in the sky when sunlight shines on raindrops. The sunlight and water work together to form rainbows. Think of sunlight flowing out in many lines, called rays. The rays are an equal distance from each other. The light energy of the rays acts similar to waves, which have different lengths. Sunlight is made up of several wave lengths. People see the mix of lengths as what is called white light. But things change when a ray of white light hits a raindrop. That is when the colors that make up white light slow to different speeds. The light bends as it enters the raindrop. This bending separates the white light into colors, each color weakening as it moves into the next color. The light rays turn or bend again when they come out of the raindrop. This continuous bending through an area of raindrops is what makes the rainbow a perfect circle.